Progressive direct taxation is necessary to complement social protection, in order to reduce income inequality as well as poverty. A new metric of personal income tax incidence progressivity (the "Plato Index") is presented, using WIDER databases for income inequality (WIID) and tax revenues...

The present paper reports estimates of welfare changes and the marginal welfare cost of income taxation for a wide range of income and demographic groups in New Zealand, in the context of a uniform increase in all marginal income tax rates. The results are obtained using enhancements to the NZ...